Refrigerating machine



March 31, 1936. c. STEENSTRUP REFRIGERATING MACHINE 2 Sheets-Sheet lFiled June 29, 1934 Inventor" Christian Steenstrup His Atborn ey.

March 31, 1936. c STEENSTRUP 2,035,769

REFRIGERATING MACHINE Filed June 29, 1934 2 Sheets-Sheet 2 Inventor:

b WW

y HisA torney.

Christi an Steen SbPup,

Patented Mar. 31, 1936 UNITED STATES PATENT OFFICE REFRIGERATIN GMACHINE Christian Steenstrup, Schenectady, N. Y., assignor to GeneralElectric Company, a corporation of New York My invention relates torefrigerating machines. It is an object of my invention to provide arefrigerating machine including an improved evaporator which shallprovide adequate cooling 5 and ice freezing capacity and shall require aminimum space within a refrigerator cabinet.

Another object of my invention is to provide in a refrigerating machinean L-shaped evaporator including an air cooling portion and a shelf forsupporting freezing trays and the like, and having an improvedarrangement for circulating refrigerant therein.

Another object of my invention is to provide in a refrigerating machinea flooded evaporator 15 having two portions and having an improvedarrangement for producing circulation of liquid refrigerant therein.

Further objects and advantages of my invention will become apparent asthe following de- 20 scription proceeds, and the features of noveltywhich characterize my invention will be pointed out with particularityin the claims annexed to and forming a part of this specification.

For a better understanding of my invention reference may be had to theaccompanying drawings in which Fig.,1 is a sectional view of a householdrefrigerator cabinet having an evaporator embodying my invention; Fig. 2is a detailed perspective view of the evaporator con- 'struction shownin Fig. 1; Fig. 3 is a detailed perspective view, in section, of theheader for the evaporator shown in Fig. 1; Fig. 4 is a sectional view ofthe evaporator on the line l4 of Fig. 2, and Fig. 5 is a perspectiveview of a modified form of the evaporator shown. in Fig. 2. Referringnow to the drawings, in Fig. 1 I have shown a household refrigeratingmachine including a cabinet having an outer wall I!) provided with apartition ll dividing the cabinet into an upper and a lower compartmentIla. A food compartment I2 is formed in the upper compartment by aninner wall or liner l3 spaced from the outer wall l0 and the partition Hand provided with a heat insulated door or cover M. The space betweenthe inner and outer walls is filled with heat insulation I5. A coolingunit or evaporator I6 secured to the inner wall I3 is provided to coolthe chamber I2 and to freeze ice, desserts. or other comestibles.Refrigerant is supplied to the evaporator Hi from a motor and compressorunit arranged within a casing I! mounted on legs l8 within the lowercompartment of the cabinet. Gaseous refrigerant is compresfed by acompressor within the casing l1 and is discharged through a. connectionl9 communicating directly with the discharge port of the compressor to acondenser conduit 2|] secured on the inner surface of the outer wall ll]of the cabinet. Refrigerant-is partially condensed within the conduit 20and passes through a tube 2| 5 to another condenser conduit 22 securedto the inner surface of the outer wall It] in the upper part of thecabinet. This condenser wherein a conduit is secured in heat exchangerelationship to the outer wall of the refrigerator cabinet is 10described and claimed in my copending application, Serial No. 554,623,filed August 3, 1931, and assigned to the General Electric Company, theassignee of my present invention. Liquid refrigerant condensed in theconduits 20 and 22 flows through a connection 23 to a receiver or floatvalve chamber 24. When a predetermined amount of liquid refrigerant hasbeen collected in the chamber 24 a float valve therein operates todischarge the liquid through a conduit 25 to the evaporator IS. Theliquid refrigerant is vaporized in the evaporator by the absorption ofheat within the chamber l2 and the vaporized refrigerant fiows through aconnection 26 to a separate spherical header 21 embedded in theinsulation I5. A level of liquid refrigerant is maintained in the header2! above the evaporator l6 so as to flood the same. The vaporizedrefrigerant which has collected in the spherical header 2! is withdrawntherefrom above the liquid level therein by the compressor through asuction conduit 28 and is returned to the casing l1, so that the casingis maintained at low pressure, and approximately at the same pressure aswithin the evaporator.

The evaporator I6 is constructed as shown in detail in Figs. 2, 3 and 4and comprises two metal sheets 29 and 30 arranged face to face. Thesheet 29 is provided with sinuous indentations or corrugations 3| and 32connected by a plurality of indentations 33. The sheets are securedtogether in any suitable manner such as by line welding around the edgesand between the indentations. The sheet 30 is made slightly larger thanthe sheet 29, and the edges thereof are bent around the edges of thesheet 29 after welding to form a smooth edge around the periphery of thesheets. The several indentations form passages between the sheets whenthey are secured together. The sheets are bent at a right angle to forman evaporator of inverted L- shaped cross-section, the indentation orpassage 3| being in the vertical portion of the L and the passage 32being in the horizontal portion of the L, which forms a shelf forfreezing trays.

The evaporator I6 is secured in good heat exchange relation to the innerliner l3 of the cabinet on bolts |6a secured to the evaporator, whichpass through holes in the liner l3 and are held by nuts |6b shown inFig. 1. The refrigerant is admitted tothe passage 3| intermediate theends thereof through a nozzle 34 at the ends of the connection 25, thenozzle being directed longitudinally of the passage to inducecirculation of liquid refrigerant therein and thereby promoteebullition. The refrigerant within the conduit 3| is induced to flowupwardly and passes through the passages 33 to the conduit 32 in thehorizontal or shelf portion of the evaporator from which it isdischarged through the connection 26 and enters the side of thespherical header 21 as shown in Fig. 3. The spherical header 21 ismaintained about half full of liquid refrigerant and is arranged so thatit will always maintain a level of liquid refrigerant above the level ofthe passage 32 in the shelfportion of the evaporator, the liquid levelbeing indicated at 35 in Fig. 1. Referring again to Fig. 3, acylindrical extension 36 is provided at the bottom of the header 21andcommunicates with the lower end of the passage 3| through aconnection 31. This connection provides a return passage affordingrecirculation of liquid refrigerant through the passages 3| and 32 inthe evaporator 16, the direction of flow being indicated by arrows. Therefrigerant vaporized within the passages 3| and 32 flows with thecirculating liquid refrigerant through the connection 26 to the header21 where it collects and is withdrawn through the suction conduit 28opening above the level of liquid refrigerant in the header.

During operation of the compressor within the casing 11 lubricating oilbecomes entrained in the refrigerant and is discharged with therefrigerant into the condenser and passes to the float chamber andthence to the evaporator. This oil will collect and float on top of theliquid refrigerant in the header 21, and it is necessary that it bewithdrawn and returned to the casing l1 in order to maintain the properquantity of oil in the casing for lubrication of the compressor. It isalso desirable that liquid refrigerant be prevented from returning withthe oil to the casing. In order to return the oil to the casing withoutalso returning liquid refrigerant, I provide a cylindrical baflie 38surrounding the open end of the suction conduit 28 provided with endplates 39 having tubes 40 for securing the cylinder within the sphericalheader 21. The plates 39 are each provided with a round hole 4| and aslot 42 whereby liquid and gaseous refrigerant and oil are admitted tothe interior of the cylinder 38. The cylinder 38 is arrangedhorizontally at right angles to the connection 26, so that gaseous andliquid refrigerant entering the header from the evaporator l6 andboiling of refrigerant do not disturb the liquid within the cylinder.The cylinder thus maintains a quiet zone within the header and the oilfloating on top of the refrigerant is withdrawn through the suctionconduit 28 as soon as a sufiicient quantity of oil is collected to reachthe top of the conduit. Since turbulence of the liquid refrigerant isprevented within the cylinder 38, and since the level of refrigerant ismaintained below the open end of the conduit 28'by operation of therefrigerating machine, liquid refrigerant is prevented from entering thesuction conduit 28. The arrangement whereby a closed cylinder having anopening at the end thereof is secured about the end of the suctionconduit to provide a quiet zone within the header is described andclaimed in a copending aplication of C. H. Steenstrup, Serial No.38,204, filed August 28, 1935, and assigned to the General ElectricCompany, the assignee of my present application; and the particulararrangement of a cylinder mounted horizontally at the end of the suctionline and provided with plates at its ends having slots extending aboveand below the level of liquid refrigerant in the header is described andclaimed in a copending application of L. W. Atchison, Serial No. 38,187,filed August 28, 1935, and also assigned to the General ElectricCompany. I do not, therefore, herein claim anything claimed in the saidC. H. Steenstrup or L. W. Atchison applications which are to be regardedas prior art with respect to this present application.

The refrigerating machine may be controlled to maintain a propertemperature of the evaporator by operation of any suitable temperatureresponsive element which is arranged within a tube 43 projectingupwardly into the cylindrical projection 36 of the header at the side ofthe suction conduit 28.

InFig. 5 of the drawings I have shown a modified form of evaporatorwhich is to be connected to theheader of the construction shown in Fig.3 in the same manner as the evaporator shown in Fig. 2. The evaporatorshown in Fig. 5 comprises two plates 44 and 45 secured together face toface by any suitable method, such as line welding, the edge of the plate45 being bent over the Welded edge of the plate 44 and the sheets beingbent at an angle to form an inverted L- shaped evaporator in the samemanner as that shown in Fig. 2. The lower or vertical portion of theevaporator is provided with a passage 46 formed by a sinuous indentationin the plate 44 and with a short vertical passage 41, these passagesbeing connected at their upper ends by a sinuous passage 48 formed by anindentation in the plate 44 in the upper or shelf portion of theevaporator. evaporator from the conduit 25 connected to the lower end ofthe passage 41. circulation of refrigerant through the passage 46 asmall duct 49 is provided connecting the passage 41 to the passage 46,so that a jet of liquid refrigerant will be directed along the passage46 and will produce an upward circulation of refrigerant therein. Itwill thus be seen that liquid refrigerant will circulate upwardlythrough the passage 46, and also upwardly through the passage 41, andthence through the passage 48 in the shelf portion of the evaporator.The connection 26 to the header 21 communicates with the passages 46 and48 at 26a. in the upper-end of the passage 46 in the vertical portion ofthe evaporator, and the return or recirculating connection 31 leadingfrom the extension 36 on the header is connected to the end of thepassage 46 at 50, so that liquid refrigerant is recirculated through thepassage 46.

During operation of this modified form of evaporator shown in Fig. 5,the greater portion of liquid refrigerant admitted through the conduit25 from the float valve chamber 24 flows upwardly through the passage 41and through the passage 48 in the freezing tray shelf where it isavailable to rapidly absorb heat for the purpose of freezing water intrays placed on the shelf.

Refrigerant flowing through the passage 46 is for Refrigerant isadmitted to the In order to induce the most part recirculatedrefrigerant flowing through the passage 26 into the header and throughthe extension 36 of the header and back to the passage 46, circulationbeing induced by the jet of liquid refrigerant admitted to the passage46 through the duct 49.

From the foregoing it will readily be apparent that I have provided animproved evaporator for refrigerating machines which requires a minimumof space within the compartment to be cooled and which provides anadequate circulation of liquid refrigerant for cooling the air in acompartment and for freezing ice.

While I have shown my invention as applied to a household refrigeratingmachine, I do not desire my invention to be limited to the particularconstruction shown and described, and I intend in the appended claims tocover all modifications within the spirt and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a refrigerating machine of the type including a cabinet having acooling compartment accessible from the top thereof, a floodedevaporator of inverted L-shaped form having a horizontal freezing shelfand a vertical air cooling portion, said shelf being accessible from thetop thereof, and means for maintaining a. level of liquid refrigerantabove the level of said shelf.

2. In a refrigerating machine, a flooded evaporator of inverted L-shapedform having a horizontal freezing shelf and a vertical air coolingportion, means introducing liquid refrigerant into said vertical portionfor producing a circulation of liquid refrigerant through said verticalportion and through said shelf, and means for providing a return passageaffording recirculation of liquid refrigerant through said verticalportion.

3. In a refrigerating machine, a flooded evaporator comprising twoportions, each of. said portions having a passage therein, meansaffording recirculation of liquid refrigerant through one of saidportions, means for supplying liquid refrigerant to said evaporatorthrough the passage in the other of said portions; and means providingcommunication between said supply means and the passage in said oneportion for diverting part of the liquid refrigerant from said supplymeans to said one portion and for producing recirculation of liquidrefrigerant in said one portion.

4. In a refrigerating machine, a flooded evaporator comprising avertical portion and a shelf portion, each of said portions having apassage therein, means affording recirculation of liquid refrigerantthrough said vertical portion, means for supplying liquid refrigerantthrough the passage in said shelf portion to said vertical portion, andmeans diverting part of the liquid refrigerant supplied through saidshelf portion for producing recirculation of liquid refrigerant in saidvertical portion.

5. In a refrigerating machine, a flooded evaporator of L-shaped formhaving a horizontal freezing shelf and a vertical air cooling portion,means affording recirculation of liquid refrigerant through saidvertical portion, means including a passage in said vertical portion forsupplying liquid refrigerant through the passage in said shelf to saidvertical portion, means diverting part of the liquid refrigerant fromsaid passage for producing recirculation of liquid refrigerant in saidvertical portion.

6. In a refrigerating machine, a flooded evaporator of inverted L-shapedform having a horizontal freezing shelf and a vertical air coolingportion, means introducing liquid refrigerant into said vertical portionfor producing a circulation of liquid refrigerant through said portionand through said shelf, means for maintaining a level of liquidrefrigerant above the level of said shelf, and means for providing areturn passage affording recirculation of liquid refrigerant throughsaid vertical portion.

. 7. In a refrigerating machine, a flooded evaporator of L-shaped formin cross-section and having a flat vertical portion and a flathorizontal portion, each of said portions having a refrigerant passagetherein, means for providing communication between said passages, meansintroducing liquid refrigerant into said evaporator intermediate theends of the passage in said vertical portion for inducing a circulationof refrigerant therein and in said horizontal portion, and meansproviding a return passage affording recirculation of refrigerantthrough the passage in said vertical portion.

8. In a refrigerating machine, a flooded evaporator of L-shaped formhaving a vertically extending portion and a horizontally extendingportion, each of said portions having a sinuous passage therein, meansfor providing communication between said passages, means introducingliquid refrigerant intermediate the ends of the sinuous passage in saidvertically extending portion for providing an upward circulation ofrefrigerant therein, and means for providing a return passage affordingrecirculation of liquid refrigerant through both of said passages.

9. In a refrigerating machine, a flooded evaporator of L-shaped formhaving a vertically extending portion and a horizontally extendingportion, each of said portions having a sinuous passage therein, meansincluding another passage in said vertically extending portioncommunicating with one end of the sinuous passage in said horizontallyextending portion and with the sinuous passage in said verticallyextending portion for producing a circulation of liquid refrigerantthrough said sinuous passages, and means for providing a return passageaffording recirculation of liquid refrigerant through the sinuouspassage in said vertically extending portion.

10. In a refrigerating machine, an evaporator of inverted L-shaped formhaving a horizontal freezing shelf portion and a vertical air coolingportion, means introducing liquid refrigerant into said evaporator forproducing a circulation of refrigerant in said shelf and in said aircooling portion, and means including a header separate from saidportions for providing recirculation of liquid refrigerant through saidair cooling portion.

11. In a refrigerating machine, an evaporator of inverted L-shaped formhaving a horizontal freezing shelf portion and a vertical air coolingportion, means introducing liquid refrigerant into said evaporator forproducing a circulation of refrigerant in said shelf portion and in saidair cooling portion, means including a header for maintaining a level ofliquid refrigerant above the level of said shelf, and means including anextension on said header for providing a recirculation of liquidrefrigerant through said air cooling portion.

12. In a refrigerating machine, an evaporator of L-shaped formcomprising sheets of metaLsecured face to face and having a horizontalfreezing shelf portion and a vertical air cooling portion, said shelfhaving a passage formed between said sheets, said vertical portionhaving a plurality of horizontal passages formed between said sheets,means introducing refrigerant into said evaporator for producing anupward circulation in the passage in said vertical air cooling portion,means connecting said passages for providing communication between thepassage in said shelf and the passages in said vertical portion, andmeans for returning refrigerant from said shelf to the passage in saidvertical portion.

13. In a refrigerating machine, a flooded evaporator of L-shaped formcomprising sheets of metal secured face to face and having a verticalair cooling portion and a horizontal freezing shelf portion, each ofsaid portions having passages formed therein between said sheets, meansintroducing liquid refrigerant into the passage in said vertical portionfor producing an upward circulation of refrigerant therein, means forproviding communication between the passages in said portions, and meansfor maintaining a level of liquid refrigerant above the level of saidshelf portion and for returning liquid refrigerant from said shelfportion to said vertical portion.

14. In a refrigerating machine, a flooded evaporator of L-shaped' formcomprising sheets of metal secured face to face and having a verticalair cooling portion and a horizontal freezing shelf portion, each ofsaid portions having passages formed therein between said sheets, meansintroducing liquid refrigerant into the passage in said vertical portionfor producing an upward circulation of refrigerant therein, meansproviding communication between the passages in said portions, meansincluding a header for maintaining a level of liquid refrigerant abovethe level of said shelf portion, and means including an extension onsaid header communicating therewith for producing a recirculation ofliquid refrigerant through the passage in said vertical portion.

15. In arefrigerating machine, a flooded evaporator for refrigeratingmachines of thetype in which lubricating oil may circulate with therefrigerant including a refrigerant circulating passage, means includinga spherical header for maintaining a level of liquid refrigerant abovethe level of said passage, means including a cylindrical extension onsaid header .for providing a recirculation of liquid refrigerant throughsaid passage, and means including a suction conduit entering saidcylindrical extension for withdrawing vaporized refrigerant from saidheader.

16. In a refrigerating machine, a flooded evaporator for refrigeratingmachines of the type in which lubricating oil may circulate with therefrigerant including a refrigerant circulating passage, means includinga spherical header for maintaining a level of liquid refrigerant abovethat of said passage, means including a cylindrical extension on saidheader for providing recirculation of said liquid refrigerant throughsaid passage, means including a suction conduit entering saidcylindrical extension for withdrawing vaporized refrigerant from saidheader, and means including a cylindrical baffle supported within saidheader and extending about the end of said suction conduit for admittinglubricating oil to said conduit and for preventing the admission ofliquid refrigerant thereto.

17. A refrigerating machine comprising a cabinet having inner and outerwalls spaced apart and provided with heat insulation therebetween, meansincluding a refrigerant circulating passage secured in heat exchangerelation to said inner wall and having a portion extending from saidinner wall for cooling theair within said cabinet and for providing afreezing shelf within said cabinet, means for maintaining apredetermined level of liquid refrigerant within said passage, and meansinjecting liquid refrigerant below the level of liquid refrigerant insaid passage for promoting ebullition of the liquid within said passage.

18. A refrigerating machine comprising a cabinet having inner and outerwalls spaced apart and provided with heat insulation therebetween, meansincluding a refrigerant circulating passage secured in heat exchangerelation to said inner wall and having a portion extending from saidinner wall for cooling the air within said cabinet and for providing afreezing shelf within said cabinet, means for supplying liquidrefrigerant to said passage, and means embedded in the insulationbetween said walls for maintaining a level of liquid refrigerant abovethe level of said passage and for providing a recirculation of liquidrefrigerant through a portion of said passage.

19. A refrigerating maching comprising a cabinet having inner and outerwalls spaced apart and provided with heat insulation therebetween, meansincluding a refrigerant circulating passage secured in heat exchangerelation to said inner wall and having a portion extending from saidinner wall for cooling the air within said cabinet and for providing afreezing shelf within said cabinet, means for supplying liquidrefrigerant to said passage, and means including a header embedded inthe insulation between said walls for maintaining a level of liquidrefrigerant above the level of said passage and for providing arecirculation of liquid refrigerant through a portion of said passage.

20. A refrigerating machine including a cabinet comprising inner andouter walls spaced apart and having heat insulation arrangedtherebetween, a flooded evaporator of L-shaped form having one portionsecured in heat exchange relation to said inner wall of said cabinet andanother portion forming a shelf for freezing trays extending from saidinner wall into said cabinet, means for supplying liquid refrigerant toboth portions of said evaporator and for producing a circulation ofliquid refrigerant through said evaporator, and means including a headerembedded in the insulation between said walls for maintaining a level ofliquid refrigerant above the level of said shelf and for providingrecirculation of liquid refrigerant through said evaporator. v

21. A refrigerating machine including a cabinet comprising inner andouter walls spaced apart and having insulation arranged therebetween, anevaporator of L-shaped form having one portion secured in heat exchangerelation to said inner wall of said cabinet and another portion forminga shelf for freezing trays extending from said inner wall into saidcabinet, means for supplying liquid refrigerant to both portions of saidevaporator and for producing a circulation of liquid refrigerant throughsaid evaporator, and means including a spherical header having acylindrical extension thereon and communicating therewith formaintaining a level of liquid refrigerant above the level of said shelfand for providing recirculation of liquid refrigerant through said evapCHRISTIAN STEENSTRUP.

